An Infiltration Perspective on the Hydrologic Legacies of Landscape Disturbance by Wildfire

Abstract:

Wildfire is a widespread disturbance that impacts soil and vegetation properties and associated hydrologic functions of water transmission and storage. Studies that examine hydrologic recovery after wildfire typically have focused on short-term (1-2 years) effects on soil properties or vegetation regeneration. The long-term recovery of soil hydraulic properties, however, may also control enhanced surface runoff and flash flood generation, especially under extreme rainfall conditions. Knowledge of the evolution of soil hydraulic properties after wildfire is essential for improving conceptual and numerical models of infiltration and runoff generation. We summarize ongoing efforts using repeated field and laboratory measurements with tension infiltrometers to examine how infiltration properties, such as field-saturated hydraulic conductivity and sorptivity, change as a function of burn severity and recovery time since wildfire disturbance. These results focus on mountainous, forested terrain in Colorado and New Mexico. We seek input from colleagues in the wildfire community regarding the duration and mechanisms of soil property recovery in other wildfire-prone landscapes to build a broader understanding.